I spent a lot of time on this topic because I plan to improve the lessons I taught last year on Digital Citizenship. My goal was to find student friendly sites where I can have students actively participate while constructing their learning. While many sites were good I found Cool Cat Teacher and http://www.kenton.k12.ky.us/internet_safety/default.htm
(thanks to VaughnL) to be the most useful.
Digital Citizenship covers so many teachable topics such as:
Internet safety-surfing safety, personal safety, courteousness, and cyberbulling
ethics-plagiarism and copyright
literacy-finding and using information AND evaluating resources
While I believe that as a librarian it is my responsibility to educate students about being digital citizens I also believe that students need these ideas re-enforced by their classroom teachers and most importantly their families.